The rinsing of phosphatized metal substrates is a usual procedure and such is typically done with a chromium-containing rinse composition. The metal substrate that has been phosphatized, as by immersion in a phosphatizing bath, while in wet condition, and often after rinsing, is then typically immersed or flooded with a chromium-containing rinse composition. Subsequently, the substrate is further water rinsed and then usually dried.
Since the phosphatizing bath may be water based, the chromium-containing rinse composition can be expected to be water based, and the subsequent drying will then volatilize water from the coated substrate. Such drying may be an elevated temperature curing operation such as taught in U.S. Pat. No. 3,063,877. These rinse compositions present the problem of an aqueous system that contains a chromium ingredient.
Chromium-containing treating compositions have been proposed that combine hexavalent chromium with tertiary alcohols. Thus, in U.S. Pat. No. 3,285,788 an anhydrous system is prepared containing such a combination in a chlorinated hydrocarbon solvent. These systems may, however, present potential flammability and operator health problems. In another approach as taught in U.S. Pat. No. 3,719,534, a dichromate salt is formed with an especial organic nitrogenous base all in an organic solvent typically further containing a reducing agent for the hexavalent chromium. The composition is suited for operations where heat curing follows coating application.
In addition to aqueous phosphatizing systems, solvent based systems such as taught in U.S. Pat. No. 4,008,101, are commercially attractive. Typical operations permit the easy removal of dry, phosphatized articles from the coating operation. These, likewise, can be subjected to chromium-containing treatments, as has been taught in U.S. Pat. No. 4,070,521. It would be desirable to have a chrome-containing treatment system that is compatible with such solvent based phosphatizing operation, which treatment system would readily provide dry coatings without heat operation and which can be compatible with aqueous based phosphatizing operations and thereby obviate potential pollution hazards accompanying the use of water baths containing chromium.